1. Field of the Invention
This invention relates to oligomers and to a method for the manufacture thereof, and more particularly to oligomers of (dihydrodicyclopentadienyl)-maleates or -fumarates and to a method for the manufacture of the oligomers.
2. Prior Art
From the disclosure of U.S. Pat. No. 3,084,147 it has been known to the art that a yellow resin having a high unsaturated bond content can be obtained by heating dicyclopentadiene at a temperature in the range of from 220.degree. to 300.degree. C. It has also been known to the art from the disclosure such as of Japanese Patent Publication No. 4552/1974, for example, that incorporation of a polar group into the polydicyclopentadiene obtained as described above is accomplished by subjecting this compound to a reaction with an .alpha.,.beta.-unsaturated carboxylic acid or an anhydride thereof.
Another method available for the incorporation of a polar group into polydicyclopentadiene is based on a procedure which comprises the steps of mixing dicyclopentadiene, prior to the initiation of its polymerization, with a polymeric monomer possessing a polar group such as an .alpha.,.beta.-unsaturated carboxylic acid, an unsaturated alcohol or vinyl phenol and subjecting the resultant mixture to thermal copolymerization at a temperature in the range of from 200.degree. to 350.degree. C. The methods touched upon above have been adopted widely in the art.
The purpose of the incorporation of a polar group into hydrocarbon resins such as polydicyclopentadiene resides in improving the compatibility of these hydrocarbon resins with high-molecular substances such as rubbers and synthetic resins with which the hydrocarbon resins are blended in the preparation of compositions and also enhancing such properties of the hydrocarbon resins as pigment-dispersing property, fluidity and adhesiveness which the hydrocarbon resins in their unmodified form fail to manifest easily.
An object of this invention, therefore, is to provide novel oligomers which possess excellent compatibility with high-molecular substances such as rubbers and synthetic resins and exhibit high solubility in various types of organic solvents.
Another object of this invention is to provide a method for manufacturing the aforementioned oligomers in high yields by a procedure capable of being easily carried out on an industrial scale.